DE2041395C2 - Process for the production of screen printing forms - Google Patents

Description

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q is a number from 0 to 5.

r is a number from 2 to 5,

R ^{4 is} hydrogen, an alkyl group with 1-5 carbon atoms, an aralkyl group with 7-12 carbon atoms or an aryl group with 6-12 carbon atoms, and

R ^{5 is an} arylene group with mito-nC atoms, and

B the remainder of an aromatic amine, phenol, thiophenol, phenol ether, aromatic Thioethers, aromatic hydrocarbon, an aromatic heterocyclic compound or an organic acid amide, each of these compounds of diuzonium groups is free and at least one capable of condensation with an active carbonyl compound Position,

50

applied as a photosensitive layer to a screen printing stencil support, the layer imagewise exposed and the unexposed areas of the layer washes out with water or an aqueous solution, thereby characterized in that a condensation product is used in which X is the anion of a Means aliphatic monosulfonic acid with 1-6 carbon atoms.

2. The method according to claim 1, characterized in that a condensation product is used, wherein X is the methanesulfonate anion.

3. The method according to claim 1, characterized in that that one uses a photosensitive mixture that the condensation product in one Quantitative proportion of 2 to 20% of its solids content bi contains.

4. The method according to claim 1, characterized in that that the photosensitive mixture in the form of an aqueous solution on the stencil support brings up.

5. The method according to claim 1, characterized in that there is a photosensitive mixture used, which additionally contains a water-insoluble filler.

6. The method according to claim 5, characterized in that the water-insoluble filler is an organic Polymer is.

7. The method according to claim 1, characterized in that the hydrophilic hardenable binder Is polyvinyl alcohol.

8. The method according to claim 6, characterized in that the water-insoluble organic polymer is a vinyl acetate polymer.

The invention relates to a method for the production of screen printing forms by means of a photosensitive A mixture comprising a condensation product of an aromatic diazonium compound and a hydrophilic curable Contains binding agent.

The use of condensation products of aromatic diazonium compounds, e.g. B. Diazodiphenylaminen, and aldehydes for screen printing is z. B. from DE-AS 1,289,741 known. It is also known that monomeric diazo compounds, 2. B. Diazodiphenylamine, preferably in combination with aldehydes give useful for screen printing layers, which crosslink upon exposure (DE-PS 1206308).

In the older German patents 2,065,733 and 2,065,732, proposals have been made, among other things. Screen printing layers from curable binders and mixed condensation products of aromatic diazonium compounds with condensable compounds and active carbonyl compounds. The condensation products are in the form of their water-soluble salts. e.g. the chlorides. In the The older patents mentioned are also the salts of the condensation products with aliphatic sulfonic acids generally described as photosensitive substances without any special properties or any Suitability for a particular purpose is indicated.

The object of the invention was to propose a method for the production of screen printing forms, which one long storage of the coating mixture in aqueous solution, a shorter exposure time than with known mixtures and development of the exposed screen printing form with aqueous solutions, preferably with pure solutions Water, made possible.

The invention is based on a process for the production of screen printing forms, in which a photosensitive mixture containing a hydrophilic hardenable binder and a condensation product of "repeating units of the general types AN ₂ X and B in an average molar ratio of 1: 0.1 to 1:20 contains, which are connected to one another by double-bonded bridge members which are derived from a condensable carbonyl compound, the units AN ₂ X being derived from compounds of the formula (R'-R ¹ -) _P R ² -N, X and where

ρ is an integer from 1 to 3,

R 'is a carbocyclic or heterocyclic aromatic radical with at least one condensable Position,

R ^{2 is} an optionally substituted phenylene group,

R- 'a single bond or one of the groups:

- (CH ₂ ^ ₁ -NR ⁴ -.

10

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-S- (CH ₂ ) ^ - NR ⁴ -,
-S-CH ₂ -CO-NR ⁴ -,
-OR ⁵ -O-,
-O-,
-S- or
-CO-NR ⁴ - mean wherein

q is a number from 0 to 5,
r is a number from 2 to 5,

R ^{4 is} hydrogen, an alkyl group with 1 to 5 carbon atoms, an aralkyl group with 7 to 12 carbon atoms or an aryl group with 6 to 12 carbon atoms, and

R ^{5 is} an arylene group with 6 to 12 carbon atoms, and B is the radical of an aromatic amine, phenol, thiophenol, phenol ether, aromatic thioether, aromatic hydrocarbon, an aromatic heterocyclic compound or an organic acid amide, each of these compounds being free of diazonium groups and has at least one position capable of condensation with an active carbonyl compound, applies it as a photosensitive layer to a screen printing stencil support, exposes the layer imagewise and washes the unexposed areas of the layer with water or an aqueous solution.

The method according to the invention is characterized in that that a condensation product is used in which X is the anion of an aliphatic monosulfonic acid with 1 to 6 carbon atoms means.

The photosensitive mixture used in the method according to the invention is distinguished from one another the mixtures of a similar type known for the same purpose due to a significantly higher photosensitivity and shelf life. The higher photosensitivity is essentially a characteristic common to all Diazo mixed condensates as described in the earlier patents mentioned above, regardless of theirs Anion is assigned, while the shelf life and water solubility are essentially determined by the anion.

In the known screen printing layers, in order to ensure aqueous developability, mainly water-soluble diazonium salts, such as halides, and sulfates, especially chlorides, are used. It was found however, that the mixtures and screen-printed layers produced with these diazonium salts are only relative have a short shelf life. In practice, therefore, the photosensitive substances were called so-called Sensitizers and the rest of the liquid copying solution are separated as a so-called screen printing emulsion stored and only immediately before their use, i.e. before the coating of the screen printing carrier, to the so-called Screen printing varnish united. It is true that diazonium salts were known to have a better shelf life in light-sensitive Layers, but these salts were always too insoluble in water for aqueous development. From this Based on experience, it was even assumed that water solubility and shelf life are mutually exclusive in the case of diazonium salts are opposing properties.

It was therefore particularly surprising that the diazonium salts used in the process according to the invention of lower aliphatic sulfonic acids have a significantly longer shelf life than those previously used water-soluble salts both in solid form and in aqueous solution and in the finished, light-sensitive Layer, although the water solubility of their preferred representatives is even that of the corresponding Chloride Exceeds.

Compared to the homocondensation products used hitherto, these diazonium salts have the other The advantage that they can easily be obtained in solid form from the condensation mixtures obtained during manufacture let out.

In the case of the photosensitive mixtures used according to the invention, it is possible to use them as finished screen printing varnishes to be stored for months in liquid form or as presensitized screen printing materials.

The aliphatic monosulfonic acids which form the anions of the diazonium condensates generally have 1 to 6 carbon atoms and can optionally not be too heavy substituents, e.g. B. halogen atoms, such as Fluorine, chlorine, bromine or iodine, hydroxyl groups, ether groups and the like. Contain. Generally is not more than one substituent present. The aliphatic chain can be straight or branched or ring-shaped. It can also contain double bonds.

Examples of suitable sulfonic acids are methanesulfonic acid, Eth \ nsulfonic acid, propane-2-sulfonic acid, propane-1-sulfonic acid, butane-1-sulfonic acid, 3-methylbutane-1-sulfonic acid, Cyclohexanesulfonic acid, hexane-1-sulfonic acid, vinylsulfonic acid, propene-1-sulfonic acid, 2-hydroxy-ethane-1-sulfonic acid, 3-hydroxy-propane-isulphonic acid, 3-methoxypropane-l-sulphonic acid, 2-chloroethanesulphonic acid, 2-bromoethanesulphonic acid and chloromethanesulphonic acid.

Mixtures of salts of two or more of these acids can also be used.

In general, the salts of sulfonic acids with more than four carbon atoms are less preferred because their water solubility is already limited. Of course, here are also the chemical nature and that Molecular weight of the condensation product must be taken into account, which also affect the water solubility. So can relatively low molecular weight condensates that contain hydrophilic groups, too have a satisfactory solubility in water even in the form of the hexanesulfonate. In general, however, the lower Sulphonates and of these especially the methanesulphonates are preferred. The latter show the best water solubility and at the same time a good storable wedge.

Another advantage of methanesulfonates over the higher sulfonates is their lower price. You let are particularly easy to produce, since methanesulphonic acid is suitable for the production of the mixed diazo condensates Condensation medium is. When they are used, the condensate falls immediately as a methane sulfate at.

The mixed condensates can, however, also be produced by condensation in acids other than the condensation medium, for example in phosphoric acid, and can contain even smaller amounts of the condensation medium without disadvantage. In favorable cases, this even increases the shelf life. An excess of precipitation agent, e.g. B. Sodium methane sulfonate, can be contained in the Diazoniunisalz used without its effect - apart from the dilution
is affected.

The preparation of the Diazopole condensals is described in detail in DE-PS 2065 732 and 2 065 733.

The condensation products can be prepared by adding at least one aromatic diazonium compound of the general formula AN ₂ X and at least one compound B. where the symbols have the meanings given above, with at least one active carbonyl compound. preferably formaldehyde, condensed in free form or with agents which release such carbon dioxide in a strongly acidic medium.

Another process for the preparation of mixed diazonium condensates of the general type mentioned above consists in using, instead of component B, a modified second component B _{1 of} the general formula

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E (-CHR ₁₁ -OR ") _m
used where

E is a residue formed by splitting off in H-Alomen from a compound B of the meaning given above,

R _u H, an aryl. Alkyl or heterocyclic radical, preferably WasserstolT,

R _{h is} H, an alkyl or aryl radical with 1-4 carbon atoms or a phenyl radical and preferably hydrogen, methyl, ethyl or acetyl and

/) / is a positive integer from 1 to about IO.

The condensation is carried out in the presence of a strongly acidic condensing agent. Preferably concentrated, moderately strong to strong acids are used.

Particularly suitable condensation fluids are phosphoric acid, Methanesulfonic acid and sulfuric acid, which in concentrations of at least 40, preferably 70 to 100, weight percent can be used. The rest is generally knowledgeable, but can also be wholly or partially from solvents. e.g., methanol, acetic acid, N-methylpyrrolidone, and the like. Good results is obtained, for example, if 80-100% phosphoric acid, 80% sulfuric acid and 90% methanesulphonic acid are used used.

85% phosphoric acid is a fairly mild condensing agent, in which the condensation can be carried out in a very gentle way. It is therefore the most preferred condensing agent, especially when using the second method, for all combinations of compounds that react quickly enough under these rather mild conditions. 90% methanesulfonic acid is a stronger agent. These Acid has the further great advantage that it can dissolve a large number of components B and B.

The average molecular weights of the condensation products can be varied greatly depending on the choice of condensation participants and conditions. It has However, it has been shown that mixed condensates with molecular weights are preferred for the production of good copier materials between about 500 and 10,000 are suitable. It is of course to be noted here that it is here are mean values.

The following groups can be mentioned which _{cause the condensability of the components AN 2} X and B:

1. Aryl radicals and heterocyclic radicals which are condensable Own core positions. Those radicals in which these core positions are still preferred are preferred are activated. This activation can e.g. B. made by fusing with weiferen uromatic rings or by substitution by groups such as -OH. -O-alkyl. -O-Arvl. -SH. -S-alkyl. -S-aryl. -Alk \ l. -Aryl. -Amino. -Alk \ lamino. -Dialkxlamino, -Aryiamino, -Diarylamino etc. In addition to these activating substituents can be used in the aromatic or heterocyclic radicals also radicals that prevent condensation, e.g. nitro and sulfonic acid groups, occur when the activation brought about by other residues is only reduced, but not canceled will.

2. Residues which are themselves accessible to condensation and directly to iso- or heterocyclic radicals or to aliphalic residues can be bound or which are optionally linked directly to one another. Belong here Groups such as carboxamides, sulfonic acid amides, N-alkyl sulfonic acid amide, N-aryl sulfonic acid amide, Nitrile, urea, thiourea, urethane, ureido, thioureido, glyoxaldiurein, imidazolone, guanidine, Dicyandiamide and amino groups attached directly to aromatic rings.

Of the diazonium compounds of the general formula

(R ¹ -R ³ -) ^ ² -N ₂ X

those in which /> = 1 are preferred. R ¹ is preferably an optionally substituted phenyl radical. Preferred substituents are those which increase the reactivity of the nucleus for the condensation, in particular alkyl and alkoxy groups. R ² denotes a phenylene group which, in addition to the diazo group, can also carry further substituents. R ³ is a link of the types given above between the radicals R ¹ and R ^{: where the radical R 1 is} always to be considered on the left and the group R ² on the right if R ^{3 is} not symmetrical.

Preferably, R ^{3 is} a homeopolar bond or one of the members -O-, -S- and -NH-.

A particularly important group of diazo compounds, which are preferred for the preparation of the diazo condensation products Find use are the salts of diphenylamine-4-diazonium ions and its substitution products.

Diphenylamine-4-diazonium salts are particularly preferred, which differ from the 3-alkoxy-4-aminodiphenylamines with 1-3 carbon atoms in the alkoxy group derive, in particular from 3-methoxy-4-aminodiphenylamine.

The compounds to be used as components B or as components B ₁ derived from them can, for example, belong to the following groups of substances:

Aromatic hydrocarbons

Aromatic amines

Phenols and thiophenols

Phenol ethers and thiophenol ethers

Heterocyclic compounds

Urea, thiourea, carboxamides

(aliphatic and aromatic)
Sulfonic acid amides

(aliphatic and aromatic)

Components B and / or B, whose molecular weight is less than 500, preferably small / than 250, is.

Preferred compounds are phenol ethers, thiophenol ethers, aromatic hydrocarbons and non-basic ones Heterocycles. Of these substance classes, those representatives that differ from

Diphenvlaiher. Diphenyl sulfide. Derive diphenylinethane and diphenyl and one or two substituents. 7. B. Halogenamines. Alkyl and alkoxy radicals, but are preferably unsubstituted.

A group of diazo polycondensates which is particularly preferred for use in the context of this invention are condensation products of 3-alkoxydiphenine-4-diazonium salts. especially 3-melhoxy-diphenylaniine-4-diazonium salts. and the above-mentioned two-part components. in particular those consisting of A - f N \ X and B ₁ under mild conditions, ie in XO 100% orthophosphoric acid at temperatures \ were prepared on 10 to about 40 ⁰ C. Such condensates are characterized by good light sensitivity and good storage stability. Particularly preferred condensate misproducts from this group include condensates of 3-methoxy-diphenylamine-4-diazonium salt and components B ₁ from the series

4.4'Bis-methoxymethyl-diphenyl ether 4,4'-Bis-niethoxymethyl-diphenyl sulfide 4.4'-bis-methoxymethyl-diphenylmethane and 4.4'-bis-methoxymethyl-diphenyl.

In particular, mixed condensates used in the context of this invention are 0.1-5. preferably 0.5 2. even more preferably contain approximately 1 mole of B or B per mole of AN ₂ X in co-condensed form.

To prepare the salts of organic sulfonic acids to be used according to the invention, one generally adds to concentrated solutions of a soluble salt of one of the Diazomischkondensaie the acid, which provide the anion should, in free form or in the form of a soluble salt, with the additive in solid substance or as a solution he follows. The medium in which the production takes place should be such that it is either the desired Salt of the aliphatic monosulfonic acid dissolves as little as possible or salting out by adding a Allowed excess of sulfonic acid or its salt.

It is advantageous to work in an aqueous solution, i.e. one dissolves, for example, crude condensation mixtures, such as those used in Production of the condensation products accumulate in water and adds the corresponding sulfonic acid or its Alkali salt in bulk or as a concentrated aqueous solution. The desired salt separates depending on the applied partners in the form of a solid precipitate that can be sucked off, or as a viscous mass from the mother liquor is separated off by decanting.

However, it is also possible to use aiipaiic sulfonic acids as condensation agents for the production of such Kundc-iisaie aliphaiische sulfonic acids apply and to separate the desired product with a non-solvent for the To mix condensation product, which however dissolves the condensation medium.

It is advantageous if the diazonium salt of an aliphatic monosulfonic acid used in the context of this invention also contains small amounts of acid, preferably H ₃ PO ,,, H ₂ SOj. or methanesulfonic acid, as this has a favorable effect on the shelf life of the product. It is particularly easy if this amount of acid comes from the condensation agent, in that this is not completely separated off. But it can also be added to the pure substance afterwards. The amount of acid should generally not be more than 2 mol, preferably not more than 0.5 mol of acid per equivalent of diazonium groups.

For the production of the used according to the invention Photosensitive compositions can contain various hydrophilic binders in combination with those described Diazo compounds can be used. Polyvinyl alcohol, partially acylated polyvinyl alcohol, partially hydrolyzed polyvinyl acetate, polyacrylic acid, methyl cellulose, hydroxymethyl cellulose and gelatin. The synthetic colloids, e.g. B. polyvinyl alcohol, partially saponified polyvinyl ester and through

Polyvinyl acetate dispersions that have been internally plasticized to copolymerization with maleates, for example, are special cheap.

You can also add fillers in finely divided dispersed form to the mixtures, for. B. in grain sizes from 5-30 μm, preferably 10-20 μm. As fillers Plastics such as polyamides, polyesters, polyurethanes and vinyl polymers, eg. B. Polyvinyl acetates, polystyrene, polyvinyl chlorides and polyvinylidene chlorides. Their use in the form of Dispersion is preferred. Finely divided silicon dioxide, aluminum oxide, Titanium dioxide, silica, clay, glass powder, metal complex dyes, color pigments. There is also the addition of plasticizers, wetting agents. Starch, salts and preservatives possible.

Water is preferably used as the solvent for the coating solution. A smaller proportion of the Solvent can also be mixed with water organic solvents, e.g. B. lower alcohols. of which methanol is preferred.

In addition to pigment dyes, the mixture can also be colored by dissolved dyes. In some In some cases, it is also useful to apply the non-colored mixture after exposure and development on the Layer support, usually a screen printing fabric to be colored. This can be done by dipping or pouring with a dye solution and rinsing off the unadsorbed excess dye. It is also possible, by dipping or pouring the alkaline solution of a coupling component after development to form a dye in the crosslinked layer, since despite sufficient light crosslinking, undecomposed, diazo groups capable of coupling are present in the layer.

is The light-sensitive mixtures lie as solid copy layers on a screen printing carrier, the materials known for screen printing serving as carriers can. First and foremost, the flat and round stencils for screen printing and textile printing come into question. These can consist of woven or non-woven fabrics or perforated foils made of plastics such as polyamide or Polyester, or from silk fabric or Japanese paper, from metal fabrics made from steel, brass or bronze or from Electroplated rotary stencils, preferably made of nickel.

The photosensitive compounds used in the mixtures also permit the addition of relatively large ones Amounts of non-water-soluble resins and other substances with undiminished ease and speed of development with aqueous developer.

The presensitized screen printing material obtained according to the invention achieves the good properties of Bichromate colloid layers known for a long time without having their disadvantages. The ones used in it Diazo compounds not only have good water solubility and storability, but are in contrast to the liquid or oily diazo condensation products customary up to now solid powder. For better confection

ίο

You can use other water-soluble powder formulations Substances such as polyvinyl alcohol are mixed.

Above all, the photosensitive mixtures and the copying materials produced with them are characterized by that it is clear compared to the diazo-based materials previously used for the same purpose are more light-sensitive and reach the light-sensitivity of comparable bichromate layers. You own on the other hand not the disadvantages of the bichromate paints, one of which is because of the thermal dark hardening very short shelf life of coated material, the short shelf life of sensitized solution, the non-constancy of the copying properties and the toxicity of bichromates are best known.

Another disadvantage of the bichromate layers is the very difficult or mostly impossible stripping hardened layers. The ability to decoat is often required for economic reasons. According to the invention produced layers, however, are characterized in that they despite excellent z. B. the pressure loads completely sufficient light networking and even after additional z. B. thermal post-curing The coating is much easier to decoat than bichromate layers. Even on nickel rotary stencils, for which, according to DE-OS 1 522 526, bichromate layers also have to be post-cured, hold the Screen printing forms obtained according to the invention without additional post-polymerization not only under high pressure loads but can also be found in the special issue 10 "Film printing stencils" of the BAYER Farben Revue, page 75, remove the coating with formic acid.

The composition of the copying layers obtained according to the invention can vary within wide limits. By adding hardenable resins and binders, the proportion of photosensitive substance in the layer can be reduced and thus the photosensitivity can be increased. For screen printing layers, the proportion of diazo condensate should generally not be less than 2%; with 5% it is already achieved that the exposed layer becomes completely water-insoluble, so that in most cases it is not necessary to use a concentration significantly higher than 5%. Of course, in certain cases, for example in the case of diazo condensates with a high proportion of second component B or B ₁ or in the case of binders which are less easily crosslinkable, significantly larger proportions of diazo condensate can also be used. In general, however, this proportion is not higher than 50%, preferably below 20%.

For layers for screen printing with solvent inks, e.g. B. commercial screen printing inks for the Printing of polyvinyl chloride surfaces, the layer only needs diazo condensate and. Colloid too exist. However, the addition of water-insoluble fillers is essential for the mechanical properties of Advantage.

If the screen printing layer for predominantly aqueous colors z. B. in textile printing are used, so recommends In order to avoid or suppress a gradual swelling, add non-water-swellable substances Substances. For such purposes, preference is given to polyvinyl acetates, especially in the form of the aqueous ones Dispersions used. The proportion of polyvinyl acetate may generally be 60-70% of the total solids content do not exceed, so that the aqueous developability is retained.

Aqueous liquids are practically always used as developers. Preferably even with pure Water developed without any additives.

The following examples are intended to illustrate the invention

however, do not limit their scope. Unless otherwise noted, percentages are percentages by weight.

example 1

12.9 g of 4,4'-bis-methoxymethyl-diphenyl ether were added dropwise with stirring to a solution of 32.3 g of 3-melhoxydiphenylimine-4-diazonium sulfil in 70.7 ml of 86% phosphoric acid. After condensation at 40 ° C. for 20 hours, the mixture was dissolved in 330 ml of water, and 240 ml of a chloride-free aqueous solution of sodium methanesulfonal containing 144 g of this salt were added. After the mother liquor had been decanted, the precipitate was redissolved in water and filled up again in the same way, separated off, dried in vacuo over phosphorus pentoxide and ground to a powder.
Yield: 37 g (C 48.0%, N 6.8%, S 10.7%, P 0.29%).

3 g of this substance were dissolved in 10 ml of water and then mixed with 100 g of an approx. 30% strength aqueous solution of polyvinyl alcohol with K-Werl 70 and a residual acetyl group content of approx. 12%, then with 5 ml of dibutyl phthalate and 10 g of finely divided Silica mixed intensively and colored with 0.2 g crystal violet. With this screen printing lacquer was coated on both sides a Perlongewebe twice, dried, dried for 5 minutes at 100 ⁰ C and exposed under a positive original using a 5000 Watt Xenon lamp at a distance of 65 cm for 2 minutes. Development was then carried out with a cold water jet, the layer being detached from the mesh at the unexposed areas with a sharp edge. After drying, the stencil could be used with the commercially available, solvent-containing screen printing inks for printing on paper and plastics.

The screen printing lacquer and the fabric pre-coated with it are at least unchanged in light sensitivity Can be stored for 10 weeks at room temperature.

Example! 2

To dissolve 32.3 g of 3-methoxydiphenylamine-4-diazonium sulfate in 210 ml of 86% phosphoric acid, 33.3 g of finely powdered 1 ^ -Bis-hydroxymethylAo-diisopropyl-benzene were added in portions with stirring. After 12 _1/2 hours of condensation at 40 ° C. and 4 _1/2 days of standing at room temperature, the mixture was dissolved in 550 ml of water at 60 ° C. and the methanesulfonate of the condensation product was dissolved by adding 800 ml of aqueous solution containing 240 g of sodium methanesulfonate contained, and deposited on cooling to room temperature. For purification, the product was redissolved in water and precipitated again in the same way, finally separated off and dried.
Yield: 50g.

With 100 g of a screen printing emulsion made from equal parts by weight of a 25% solution of polyvinyl alcohol with a K value of 75 and a residual acetyl group content of about 12% and a dispersion of a vinyl acetate copolymer with 55% solids content existed, the aqueous solution of 2 g of the diazo compound prepared as just described was stirred.

A polyester screen printing fabric was coated, dried, exposed and developed with water as usual and dried. In order to make the image more visible, the stencil was developed before drying

colored by pouring an aqueous solution of crystal violet over it. Not the one at the shift parliaments Adsorbed excess dye was removed by rinsing before drying. The screen printing stencil is excellent for printing textiles with the usual aqueous textile printing inks.

Example 3

25.9 g of 4,4'-bis-methoxymethyl-diphenyl ether were added dropwise with stirring to a solution of 42.5 g of 2,5,4'-triethoxydiphenyl-4-dia / oniumsulfal (N 6.2%) in 300 ml of 93% phosphoric acid. After 3 to ₄ hours of condensation at 4 ° C., the mixture was diluted with 30OmI of water and the methanesulfonal was deposited by adding 860 ml of 26% strength meihansulfonic acid solution, separated off after repeated reprecipitation and net rock.

Yield ": 67.3 g (C 48.1%. N 3.0 ". S 8.1 ", P 3.8%).

Hine approx. 30% polyvinyl alcohol solution, which through 8 hours of stirring polyvinyl alcohol with a K value of 50 and a residual acetyl group content of approx I2% p had been produced in water at approx. 85 ° C in an open kettle. with 1% polyethylene glycol as Antifoam added / t was in the weight ratio 3: I with the 55% dispersion of a vinyl acetate maleina ! -Mischpolymerisats mixed. In 25Og des 4 g of the water-soluble diazo compound described above were stirred into the mixture.

A screen was coated with this printing varnish, dried, exposed, developed and the so produced Screen printing stencil used for printing on PVC plastics. She is free from shift teachers. the so-called grease eyes, and therefore usable for high areas without covering work. If the stencil doesn't is used more, the fabric can by desizing, z. B. with chlorinated lime or sodium hypochlorite, preferred with lithium hypochlorite solution, cleaned and reusable.

Example 4

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35

40

To a solution of 32.3 g of 3-methoxydiphenylamine-4-diazonium sulfate 25.8 g of 4,4'-bis-methoxymethyl-diphenyl ether were added to 100 ml of 86% phosphoric acid with stirring dripped. After 17 hours of condensation at 40 ° C, the methanesulfonate became as in the previous one Examples described deposited, cleaned and dried.

Yield: 53 g (C 55.3%. N 6.5%, S 6.2%. P 1.9%. Cl <0.1%, H, O 4 - 3%). so

To 1000g of a screen printing emulsion. which consisted of 3 parts of a 53% strength vinyl acetate copolymer dispersion and 2 parts of a 24% strength solution of the polyvinyl alcohol used in Example 2, prepared by dissolving and concentrating, were an aqueous solution of 15 g of the above-described diazo condensate and 4 g of a blue one Dye given and stirred with it. A perforated nickel roling cylinder with 576 meshes / cm ^{2 was} coated 3 times with intermediate drying with this copying lacquer by moving a round rubber squeegee filled with it upwards on the outside of the upright perforated cylinder. The holes of the rotary cylinder were filled with photosensitive varnish. After circular exposure with a mercury vapor tube lamp. with the cylinder slowly rotating with the original attached, the layer was removed from the holes in the unexposed areas with a shower of water. The round template, which was almost free of hairline cracks, was then somewhat retouched and post-hardened by tempering at 150-180 ° C. and made ready for printing. With this printing form, large quantities of textiles could be printed. The printed out nickel rotary stencil can be decoated with formic acid so that the perforated rotary cylinder can be used again.

Example 5

The condensation mixture of Example 4 was condensed for 5 hours at 40 ° C and the condensation product as described there in the form of the salt Chloromethanesullbic acid deposited.

With an aqueous solution of 4 g of this substance, 250 g of a 30% strength solution of the in Example 1 used polyvinyl alcohols, the 5%! "one-part polyvinyl acetate powder contained, sensitized. So that was as usual by coating. Drying, exposure. To develop. Drying made a screen printing stencil.

Example 6

The procedure of Example 5 was used to produce the diazo condensate. However, the deposition took place in Form of the salt of propane-2-sulfonic acid.

A 10% aqueous solution of hydroxyethyl cellulose was stirred with 1% of the photosensitive compound described above. By 3 times double-sided coating of a fine-mesh screen print fabric as well as exposure. Developing with water and drying has made a good stencil for solvent ink screen printing manufactured.

Similar results were obtained when the Dia-7ocondensate deposited as a salt of butane -! - sulfonic acid and otherwise processed in the same way.

Claims (1)

Patent claims: 1. A process for the production of screen printing forms, in which a photosensitive mixture containing a hydrophilic hardenable binder and a condensation product of recurring units of the general types AN ₂ X and B in an average molar ratio of 1: 0.1 to 1:20, which among each other are connected by double bonded bridge members which are derived from a condensable carbonyl compound, the units Α - Ν-, Χ being derived from compounds of the formula (R ¹ -R ³ -) _P R ² -N, X and where
ρ is an integer from 1 to 3, R ^{1 is} an aromatic radical with at least one for condensation with active carbonyl compounds qualified position,
R ^{2 is} an optionally substituted phenylene group,
R ^{3 is} a single bond or one of the groups: - (CH ₂ ), -NR ⁴ - -0- (CH,) _r -NR ⁴ - -S- (CH,) _r -NR ⁴ - -S-CH ₂ CO-NR ⁴ - -OR ⁵ -O- -O- - S - or -CO-NR ⁴ - 25th